Are You Hearing This?

Are You Hearing This?

Frank Lin’s research ties hearing loss to dementia, with big implications for public health: Unbundled, accessible audiology services and reimbursement for audiologic rehabilitation could be key, he says, to battling cognitive decline associated with hearing loss.

Spend some time listening to Frank Lin talk about dementia, and you’ll never look at hearing loss the same way.

Research by Lin and his team reveals a strong association between untreated hearing loss and the risk of cognitive decline and dementia in older adults—a link that poses big public health problems because of the aging population, says Lin, an associate professor of otolaryngology-head and neck surgery, geriatric medicine, mental health, and epidemiology at Johns Hopkins University.

As many as 5 million Americans age 65 and older have Alzheimer’s disease—just one specific type of dementia—and that number will increase significantly with current population trends, according to the National Institute on Aging, unless something’s done to treat or prevent it.

Lin’s work focuses on three main questions surrounding the dementia-hearing loss link: What are the consequences of hearing loss (which affects about two-thirds of everyone older than 70) for older adults? Does treating hearing loss make a difference? And how do we address the issue from a big-picture, societal perspective?

Lin, who will be the opening speaker at the research symposium during the ASHA 2015 Convention, spoke with the Leader about his work, the future of hearing health care and what that all means for older adults.

Do we have any insights into the association between hearing loss and cognitive decline and dementia?
There are several different ways we think that hearing loss can be related to cognitive decline and dementia. The most intuitive reason for a lot of people is that it’s just some type of common cause—aging, for instance, or some type of common neurodegenerative process between the ear and the brain, or maybe things like hypertension and diabetes, conditions that cause small-vessel disease. We don’t think it’s only that though, mainly because in these very large epidemiologic studies, when we controlled and adjusted for all those factors, we’re still seeing a very, very strong association between hearing loss and dementia. We think it’s unlikely that that’s explaining away the entire effect, so it’s not just purely correlation.

There are three likely mechanistic pathways in which hearing loss could directly contribute to dementia. The first idea is that hearing loss leads to a “cognitive load” on the brain, meaning that if the cochlea is constantly sending a very garbled signal to the brain, which is what happens as we develop hearing loss, the brain has to rededicate cognitive resources—brain power—to constantly deal with and decode that very degraded auditory message. And possibly that cognitive load, in turn, leads to a decrement in our other cognitive and thinking abilities.

The second idea is that hearing loss may directly lead to changes in terms of the brain structure and function. We’re seeing a lot of studies now across a variety of different datasets that hearing loss can actually lead to structural changes in the brain, with faster rates of atrophy in parts of the lateral temporal lobe, which is the part that handles sound processing. But importantly, those same parts of the brain also handle other parts of language and memory, so if you have a very impoverished signal ascending to the brain, it makes sense you may have faster atrophy over those regions. But those parts of the brain are important for other cognitive functions as well.

The third idea related to the observation is that hearing loss directly contributes to social isolation. Older people with hearing loss are not as likely to be engaged with people around them and not likely to be engaged in social activities. And yet, we’ve long known that social isolation is a clear risk factor for cognitive decline and dementia. So, in the end, we think there are three possible pathways by which hearing loss could directly contribute to increased risk of cognitive decline and dementia.

If the cochlea is constantly sending a very garbled signal to the brain, which is what happens as we develop hearing loss, the brain has to rededicate cognitive resources—brain power—to constantly deal with and decode that very degraded auditory message.

What does your research say about hearing aids? Can using them help minimize the effect of hearing loss on cognitive function?
Quite simply, we don’t know yet. The reason for that is because in observational studies—with people recruited from the community—it’s very hard to look at the effect of hearing-aid use in isolation, mainly because the people who use hearing aids may be fundamentally different than people who don’t use hearing aids. For example, they may be more affluent, socially engaged and health-conscious. It’s very hard to tease apart the effect of hearing-loss treatment or hearing-aid use from these other factors.

Could hearing-loss treatment actually help reduce cognitive decline or dementia? Again, we don’t know yet. We have funding for an initial phase of a much larger study that will test that very question—namely, if you take a large group of older adults, all of whom have some hearing loss but are otherwise cognitively normal, and if half get hearing loss treatment and the other half just get watchful waiting, can cognitive decline or dementia be delayed or avoided?

What are the implications of your research for audiologists, and what can they do to help their older patients with hearing loss?
I think there are a couple things. One key observation is that a lot of people see hearing loss as a normal—and thus inconsequential—part of aging. Even some health care providers have this point of view. From a population-based perspective, hearing loss exerts very real and significant effects on our health and functioning as we age.

Along with that, though, I think the way hearing health care is delivered in the United States is essentially as a “Cinderella” service. It’s one of those services that you’ll only receive if you can afford the cost and have the wherewithal to jump through all the hoops to pursue it—and our current hearing-health-care system propagates that model. Namely, assuming that if you have $4,000, you can get help. And if you can’t—then, well, too bad. I think that attitude has to go. We need to make hearing health care a lot more affordable and accessible.

We need to make hearing health care a lot more affordable and accessible.

Do you have any advice for families of people who are either at risk for hearing loss or are experiencing it?
I think the most important thing is—and this goes for all of the clinicians among us, too—that hearing health care doesn’t have to be complex. The goal of hearing health care is simply to help someone have the means to communicate effectively. Some people just need good communication strategies and an understanding of how hearing loss manifests. Other people may need a simple sound amplifier, which could range from a hearing-aid-like PSAP [personal sound amplification product] to a pocket talker [simple amplification system]. Others may need a custom-fit hearing aid that’s programmed using best practices. And finally, some may need comprehensive rehabilitation, incorporating a full needs assessment, counseling and provision of multiple hearing technologies.

Do you have any advice for speech-language pathologists when it comes to working with patients who have hearing loss?
People underestimate the effect that hearing loss can have on daily functioning and communication. In an assisted living facility, for example, staff may overlook simple communication strategies, such as speaking face-to-face or first getting the patient’s attention. And when someone has a hearing problem, it may help to just pull out a pocket talker and put it on the person to see if it helps.

In almost all cases, general staff (not SLPs and audiologists) at assisted living facilities have the impression that the only way to help patients with hearing loss is to get them a hearing aid, which may not always be practical, feasible or even the best option. In these cases, teaching the care provider about some basic communication strategies and showing them how to use a pocket talker doesn’t take much time and can make a huge difference.

What are some future trends in addressing hearing loss as a public health problem?
I think there are several things. There’s clearly a need to unbundle services so that, even if a person only has a few hundred dollars, that person can still get some help. This would likely involve the audiologist charging a fixed rate for consultation/evaluation and helping instruct the patient in using some type of over-the-counter amplification device. The vast majority of PSAPs on the market now are terrible, but there are a select few that work well for some individuals. As clinicians, we should know these devices and be able to help our patients distinguish between what is good versus bad.

In the future, I could foresee an insurance reimbursement model where an audiologist’s time for providing rehabilitative services is covered, and expenses for purchasing a device are reimbursed separately. Hearing devices, as with any other electronic device, will only go down in cost over time; it’s inevitable. So it doesn’t make sense to tie services to a device when devices always get outdated and outmoded very, very quickly, but our services and expertise never will.

Beyond that, there is movement at the national level where the Institute of Medicine [IOM] is tackling this issue. Last year, in January, they hosted a formal two-day workshop on the topic of hearing loss and healthy aging. And now they’ve initiated a formal consensus study and have convened a panel of diverse experts to recommend ways to increase affordability and accessibility of hearing health care for adults. This IOM study has the clear potential to lead to change in both the regulatory and reimbursement domains.

Another trend is toward developing other, more accessible, models of care rather than a patient having to go back and forth to a clinician’s office to receive care. Several groups around the country are beginning to develop programs to train community health workers to go out into the field and provide hearing screenings, as well as to provide services at a very basic level (for example, educational counseling, provision of an over-the-counter device, referral as needed). Using community health workers for managing common chronic conditions in adults has been common throughout public health for, say, diabetes screening and management, cancer screening and management, and mental health counseling.

In terms of technology, PSAPs are evolving into wearable devices—that is, ear “hearables,” where the distinction between a consumer electronic device versus a hearing aid is rapidly blurring.

What drew you into this field, and what excites you about it?
In medical school, I was really drawn to surgery because I liked the idea of having an immediate impact, whereas other fields of medicine aren’t necessarily like that. At the same time though, with my focus on epidemiology, I’m clearly doing a nontraditional sort of ENT research, per se, which comes from my parents, who are both public health researchers. They’ve been driven by the big questions—questions that can affect thousands and millions of people at a time—so they were surprised when I chose to do surgery because it’s the opposite, one patient at a time.

But even though I liked the immediacy of surgery, I was still more academically drawn to the big questions, and not necessarily how can we perfect a surgery a little more, or more molecular-based research. What attracted me were those big, conceptual questions—namely, does hearing loss have an important impact on older adults and does it affect healthy aging and dementia? (Dementia is arguably one of the biggest public health concerns for the next 40 years).

As with many other people, I have personal experience with hearing loss as well: My grandmother, who I grew up with, has had a moderate-to-severe hearing loss for several decades, and I’ve always observed the effects that it seems to have on her. My choice of going into otology and pursuing my current line of research has been a product of many things—my personal enjoyment of doing otologic surgery, my interest in the broader conceptual and academic public health questions facing society, and my personal experience as well.